(() => {
  /* 1. ECMAScript 的内置对象 */
  let b: Boolean = new Boolean(1)
  let n: Number = new Number(true)
  let s: String = new String('abc')
  let d: Date = new Date()
  let r: RegExp = /^1/
  let e: Error = new Error('error message')
  b = true
// let bb: boolean = new Boolean(2)  // error


})();

(() => {
  const div: HTMLElement|null = document.getElementById('test')

  const divs: NodeList = document.querySelectorAll('div')
  const handleClick = (event: MouseEvent) => {
    console.log(event.target)
  }
  document.addEventListener('click', handleClick)
  const fragment: DocumentFragment = document.createDocumentFragment()
})();